Hearing loss loci segregating in consanguineous families from India and Pakistan were ascertained. Each family consisted of at least four affected children related to each other through a consanguineous union. Three families mapped to DFNB3 and have mutations in MYO15. One family provided information for localization of the DFNB7 locus. The fourth family is linked to a new locus, DFNB18. The information for the DFNB18 locus will be submitted for publication. A large number of additional consanguineous Indian families with nonsyndromic hereditary hearing impairment have recently been ascertained which support LOD scores over 3. DNA samples from these families are being analyzed for localization to known loci. Any families unlinked to the known DFNB and DFNA loci will then be mapped to find additional locations for recessive loci causing nonsyndromic hereditary hearing impairment.